Modulating lamp assembly and circuit therefor



sept. 22, 19361 A. LGE 2,054,846

MODULATING LAMP ASSEMBLv AND CIRCUIT THEREFOR Filed sept. 13, 1935 5Sheets-sheet 1 ATTORNEY Sept. 22, 1936. A Z|LLGER 2,054,846

MODULATING LAMP ASSEMBLY AND CIRCUIT THEREFOR 6M um .D ATTORNEY Sept.22,1936. A. ZILLGER 2,054,846

MODULATING LAMP ASSEMBLY AND CIRCUIT THEREFOR Filed Sept. l5, 1935Sheets-Sheet 3 Patented Sept. 22, 1936 lUNITED STATES PATENT OFFICEMODULATING LAMP ASSEMBLY AND CIRCUIT THEREFOR Application September 13,1933, Serial No. 689,255 s claim. (ci. 17e-.122)

This invention relates to gaseous discharge lamps particularly adaptableto high frequency modulation such as might be'used for television orsound-on-fllm recording, and includes an operating circuit for suchlamps as well as a mounting bracket therefor.

One of the objects of the invention is to provide a gaseous dischargelamp which is easy to start and which may not be readily extinguishedwhile in operation.

Another object of the invention is to provide a means for starting agaseous discharge lamp without raising the voltage substantially beyondthe operating voltage.

Still another object of the invention is to provide a means for mountinga gaseous discharge lamp.

A still further object of the invention is to provide a means forincreasing the light of a gaseous discharge lamp in a given direction.

Other objects of the invention and objects relating particularly to themethod of constructing and assembling the various parts will be evidentas the description of the invention proceeds.

Several forms of the invention have been illustrated in the accompanyingdrawings in which:

Fig. 1 is a. front elevational View partly in section of a tubulardischarge lamp mounted in a supporting standard;

Fig. 2 is a. plan view of the lamp and standard -shown in Fig. 1;

Fig. 3 is a sectional plan view taken on the line 3-3 of Fig. l;

Fig. 4 is a side elevational view of a modified form of the lamp andstandard;

Fig. 5 is a sectional plan view of the lamp and standard shown in Fig.4, taken on the line 5--5 of that gure;

Fig. 6 is a sectional plan view of the lower con nector taken on theline 6 6 of Fig. 4;

Fig. '7 is a side elevational view of a modified form of lamp mounted inits supporting standard;

Fig. 8 is a sectional plan view of the tubular portion of the lamp takenon the line 8- -8 of Fig. 7:

Fig. 9 is a sectional elevational view ci the lower base of the lampshown in Fig. '7 showing the means for making some of the connections;

Fig. 10 is a plan view partly in section of the socket for supportingthe lamp of Fig. '1;

Fig. 11 is a front elevational view of a modified form of lamp showingits supporting sockets;

Fig. 12 is a bottom view 0I the construction shown in Fig. 11; and

Fig. 13 is a circuit diagram showing one manner of connecting the lampin a circuit.

Referring now more specifically to the drawings the lamp of Fig. 1comprises a bulb I of glass or other transparent material at the upper 5end of which is formed an inwardly extending press 2 similar to thatused on a radio tube or electric light bulb which has a singlesupporting wire 3 upon which is mounted a cathode 4. The cathode 4 inthe present instance is formed of 10 a strip of wire mesh rolled uponitself and attached to the support wire 3. The mesh may be made ofnickel. tungsten, molybdenum, tantalum, iron, or the like. Between thecathode 4 and the press 2 is positioned a disc 5 of mica or other suit-15 able insulating material. The upper end of the bulb I may be providedwith a metallic cap 6 to which the lead-in wire 1 from the cathode maybe attached as by soldering. The cap 6 may be heid in position by anysuitable plastic cement.

A second bulb 9 shown at the lower end also has an inwardly extendingpress I0 upon which is mounted a single support rod I i terminating atits upper end at a point adjacent the wall of the bulb in a cup-shapedanode I2.

The bulb 9 is provided with a metallic base I3 similar to the upper base6 and to which the lead-in wire i4 connected to the support rod l I maybe attached as by soldering. A disc I2'l of mica may be positionedbetween the anode and 30 the press to protect the latter against thedischarge.

The two bulbs I and 9 are connected together by means o1' a glass tubeI5, the tube being fused to both of the bulbs so that there is agas-tight 35 communication between them. 'I'he diameter of the tube i5may be determined by the diameter of the light source desired and theintensity of the light desired, as the smaller the tube is in diameterthe more intense will be the illumina- 40 tion. For the purpose of atelevision light, a. tube about 1A inch in diameter has been found togive excellent results. While the length of the tube may be left to thediscretion of the designer, one nine inches long was used successfully.'I'he 45 lamp may be filled with an inert gas such as neon, argon,helium, krypton, or xenon or mixtures of such gases may be used, ormixtures of any or all of such gases with a metallic vapor such asmercury vapor or sodium vapor may be used, 50

depending on the color of the light desired and the particular use towhich it is put. The pressure of the gas may be in the neighborhood of10 mm. of mercury.

With a lamp constructed in this manner it has been found that thevoltage necessary to start the discharge is somewhat higher than theoperating voltage of the lamp and it has been found necessary heretoforeto provide some means to give an impulse of a. higher voltage in orderto get the lamp started. 'I'his has been done by an induction coil withthe secondary connected through a spark gap across the terminals/of thelamp, and also by a high resistance choke which may be shorted acrossthe lamp and then suddenly released. It has also been found that aparticularly heavy surge in the current operating the lamp may cause thelamp to go out with the result that the before mentioned operation mustbe again resorted to in order to continue its operation. I have foundthat I can lower the necessary starting voltage of the lamp to aconsiderable extent and also prevent the lamp from going out upon itsreceiving heavy surges, or at least to cause it to immediately lightagain without any additional external inuence, by providing a conductorin close contact with one side of the tube throughout its length andconnecting that conductor to ground or to some point on the operatingcircuit.

In order to provide the grounded conductor as explained above and alsoto make a suitable bracket or support' for the lamp I provide a. rec.-tangular support it of wood, a phenolic condensation product, hardrubber, or other insulating material, preferably somewhat heatresisting, upon which I fasten at the upper end a spring clamp il toreceive and support the cap E at the top of the tube and a second springclamp i8 at the lower end to receive and support the cap i3. The springsupports il and i@ are similar in construction and may comprise asubstantially U- shaped fiat strip of spring metal the legs of whichhave curved portions i@ to t around the cap at the end or the tube,there being outwardly bent ends 2li to facilitate the insertion of thecap in a manner clearly understandable from an inspection of Figs. 2 and3. The base 2| of the clamp may be attached to the support by means ofthe bolts 22 as indicated in Fig. 2. Each y clamp may also be providedwith a lug 23 for making the electrical connection to the lamp by meansof a wire soldered thereto. Thus the wire 2 may be attached to the upperclamp and a wire 25 may be attached to the lower one so that when thelamp is inserted in the clamp the electrical connections will be made tothe anode and cathode.

I also provide on the support it a semi-cylindrical metallic member 26which hasl a sufiicient diameter so that it will just t around half ofthe tube. This element 26 is preferably highly polished on its interiorface so as to redirect any light directed against it back again throughthe tube and out the other side. The element is supported upon aplurality of spring supports 21 which may be bent to form a sinuouscurve as indicated in Fig. 3, and which may be attached to the supportby means of the bolt 2li. One of these supports may be connected toground as by means of the wire 29 shown in Figs. 1 and 3. By means ofthe resiliency of the supports 2l it is possible to withdraw thereflecting element 26 slightly to the left while the tube is beinginserted and thereupon permit it to move to the right where it falls inplace, held firmly against the wall of the tube.

It will be seen that this construction permits easy insertion andwithdrawal of the tube at the same time insuring the snug attachment ofthe grounded element.

In Fig. 4 a modiiled construction is shown wherein lthe entire lamp ismounted by means of the-tubular element. To this end a lamp 30 is shownhaving a bulb 3l at the top and a second bulb 32 at the bottom connectedby means of the tube 33. A semi-cylindrical metallic member 34 issupported in `spaced relation upon the base 35 by means of supportmembers 36 which may be held in place by suitable bolts 31. Thesemi-cylindrical conductor 3e may be provided at its ends with extendedclips 38 adapted to spring over the tube 33 to hold it securely in themember Sii. The member Sli may also be polished on its interior surfaceso as to form a reector for the lamp in addition to the groundedconductor. One of the supports 36 may, of course, bel grounded as by theWire 39 shown at the lowermost support.

With this type of lamp I may provide insulating caps it on the upper andlower end of the lamp with metallic pins 4i extending outwardlytherefrom. The electrical connections may be made by spring terminals i2which may clip over the ends of the pins 4l as is clearly indicated inFig. 6. Any suitable connectors may of course be used for this purpose.

In the foregoing figures I have shown the grounded conductor element tobe a separate part of the lamp. It can, howeverr be integrally formed asa part oi the lamp if desired. Where such a construction is desired themost convenient way may perhaps be to silver one side of the tubularportion of the lamp as is indicated in Figs. '7 and 8, where the lamp d3comprises an upper bulb it and a lower bulb i5 connected by the tubularmember 35. This tubular member has half of its outer surface coated withthe silver surface il which may be applied in the same manner as thesurface is applied to an ordinary mirror, or may be painted upon thesurface of the glass, or sprayed on, or put on in any desired manner, ascementing a piece of foil thereon.

For this type of lamp I have shown a metallic cap d@ on the upper bulbwhich may be sprung into spring clips Eid, similar to those alreadydescribed, acting not only to support the upper end of the lamp but tomaire the electrical connection thereto by means of the wire te. L haveshown an ordinary vacuum tube base di on the lower end of the lampprovided with two pins 52 and 53, The first pin 52 may be connected bymeans of the wire 5d to the cathode 55, (shown in Fig. 9) while the pin53 may be made smaller in diameter andmay be connected outside of thelamp to the silvered surface lll by the expedient of extending thissurface downwardly in a strip 55 around the surface of the lower bulb.

pushed down upon a socket 56 provided with a pair of spring receptacles57 and 5t, one for the large pin 52 and the other for the smaller pin53. A lug 59 attached to the clip 5l? may be used for making theelectrical connection of the lamp while a lug 6B attached to the spring58 may be grounded by means of the wire 6i for grounding the conductingsurface il on the tube of the lamp.

The upper clip 49 may be attached to the top of an insulating support 62while a ange 63 integral with the lower end of the support 52 mayreceive the socket 66 and hold it in place by means of a suitable bolt64. Thus both the cathode and grounded shield are connected by merelyinserting the lower lamp base into the socket provided for it. In Fig.10 the plan view of the socket shown in Figs. '1 and 9 indicates the useof a standard four point socket for this purpose, two only of theterminals being used.

While the foregoing figures show a lamp in which the axes of the endbulbs are in a line with the tube of the lamp it may be desirable to usethe construction of Fig. 11 wherein the bulbs have their axes at rightangles to the tubular portion of the lamp. In this construction the lamp65 has its upper bulb 66 and lower bulb 61 lying with their axesparallel to each other while the straight or tubular portion 68 has itsupper and lower ends bent at right angles at 69 and 10 to enter thebulbs 65 and 61. The bulb 66 is provided with a metallic cap 1| whichfits into a spring clip 12 secured to the base 13 while the bulb 61 isprovided with a metallic cap 14 which iits into a spring clip 15.

The reflecting conductor member 16 is supported in spaced relation v.tothe upright 13 by means of a spring 11 attached to the upright 13 by thescrew 18 to which may be secured the wire 1S leading to ground.Thespring 11 gently urges the conducting reflector 16 outwardly againstthe tube 68 of the lamp so that good contact is insured at all times.

In Fig. 13 a circuit diagram of one way of connecting the lamp is shown.Here three output power tubes connected in parallel are shown mounted inone envelope as described and claimed in my application Serial No.689,256, filed September 13, 1933. The tube 80 has the three plates 8lconnected together and to the cathode terminal 82 of the lamp 83 bymeans of the Wire 84, while the anode terminal 85 may be connected to apositive potential as for instance to the B battery 85a the negativeside of which is of course grounded. The laments 86 of the tube areconnected in parallel and to a suitable source of filament current,there being a resistor 81 across the filament circuit with its midpointconnected to ground through a resistance 88 and a by-pass condenser 89.The grids 9U are also connected together and by means of a wire 9i toone side of the secondary 92 of a transformer 93, the other side of thesecondary being connected to ground by means of a wire 94. The primaryof the transformer 93 may have its ends connected to the plates of apair of amplifying tubes arranged for push-pull amplification in amanner well known in the art and as also described in the applicationlast above referred to. The conductive shield 96 is grounded as at 91and when thus connected produces the beneficial results described above.

With this invention I have provided an improvement over the type of lampheretofore used for modulating purposes in that the starting voltage ofthe lamp is greatly reduced. It is only necessary to turn on the amplierfilament and plate supply to have the lamp light up, even before thetubes come up to their proper temperature, and all necessity of anyadditional operation upon the lamp to start it is eliminated. Also it isagain pointed out that the operation of the lamp is greatly improvedbecause it will seldom go out due to a sudden surge of current and ifsuch occasion should arise it will immediately light itself again sothat no attention need be paid to it nor is it necessary to provide anyauxiliary starting apparatus.

While in all of the cases I have shown the conductive reflecting memberconnected to ground it may also be connected either to the anode ortubes have all been shown straight in the various figures but the lampmay be constructed with much longer tubes and with the tubes bent in anydesired configuration, as, for instance, to form letters. I, therefore,do not desire to limit myself to any particular type of construction ofthe lamp but I wish tointerpret the invention broadly limited only bythe scope of the appended claims.

What I desire to secure and claim by Letters Patent is:

1. -A- lamp comprising an envelope, an anode within said envelope, acathode within said envelope andspaced from said anode, a restrictedpassage'between said anode and cathode, a support, means to secure saidenvelope to said support, a separate movable, conducting member, andmeans mounted on said support to hold said conducting member in closeproximity to said restricted passage.

2. A lamp comprising a tubular member, a bulb at one endv of saidtubular member, an anode within said bulb, a second bulb at the otherend of said tubular member, a cathode within said second bulb, anionizable gas within said tubular member and bulbs and surrounding saidanode and cathode, a support, means to releasably attach one of saidbulbs to said support, means to releasably attach the other of saidbulbs to said support, a separate movable conducting member, and meansto hold said conducting member in close proximity to said tubularmember.

3. A lamp comprising a tubular member, a bulb at one end of said tubularmember, an anode within said bulb, a bulb at the other end of saidtubular member, a cathode within said second bulb, a cap on the end ofone of said bulbs, means to connect the anode to said cap, a cap at theend of the other of said bulbs, means to connect said cathode to saidcap, a support, means to releasably attach one of said caps to saidsupport, means to releasably attach the other of said caps to saidsupport, a separate, movable, semi-cylindrical conductor, and meansmounted on said support to resiliently urge said semi-cylindricalconductor against said tubular member.

4. A lamp comprising a tubular member, a bulb at one end of said tubularmember, an anode within said bulb, a second bulb at the other end ofsaid tubular member, a cathode within said second bulb, a metal cap onthe end of said first bulb and connected to said anode, a second cap onthe end of said second bulb and connected to said cathode, a support, ametallic spring clip on one end of said support and adapted toreleasably hold said anode cap,` a second metallic spring clip on theother end of said support and adapted to releasably hold said secondcathode cap, and a separate, movable, conducting member in contact withthe outer surface of said tubular member.

5. A lamp assembly comprising a tubular.

transparent member, a bulb connected on one end of said member, an anodewithin said bulb, a

second bulb connected on the opposite end ot said member, a cathodewithin said second bulb. an ionizable gas within said bulbs and tubularmember including neon and a small amount of a metal vapor, a conductorextending longitudinally of said tubular member and in close contactwith the outer surface thereof, a base attached to one of said bulbs,`apair of terminals on said base, means to connect one of said terminalsto the element within said bulb, means to connect the other of saidterminals to said conductor on said tubular member, a support, a socketmounted on said support, and adapted to receive said base, and means toreleasably secure the other bulb upon said support;

6. In a lamp assembly a transparent tubular member, a bulb integral withone end of said tubular member, an anode AWithin said bulb, a secondbulb integral With the other end of said tubular member, a cathodewithin said second bulb, a support, a conducting member rigidly securedin spaced relation to said support, and means to releasably secure saidtubular member to said conducting member so that it is maintained inclose contactftherewith.

7. -A lamp assembly comprising a tubular member, a bulb at one end ofsaid tubular member and extending at right angles thereto, a second bulbat the other end of said tubular member and extending at right anglesthereto,` an anode within said iirst bulb, a cathode within said second'bulb, an inert gas and a small amount of a metal vapor within said bulbsand tubular member, a cap on said first bulb and connected to saidanode, a cap on said second bulb and connected to said cathode, asupport, means to releasably hold said caps upon said support, aconducting member having substantially the same length as said tubularmember, and means to mount said conducting member upon said support insuch a position that it will lie against said tubular member when thelamp is positioned on said support.

8. A lamp comprising an envelope, an anode within said envelope, acathode within said envelope but spaced from said anode, an ionizablegas within the envelope, a restricted passage between said anode andcathode, asupport, means for holding said lamp upon said support inoperative position with reference to an electric circuit whereby adiii'erence cf potential is applied between the anode and cathode, andadditional means attached to said support and effective only when saidlamp is in said operative position, for modifying the breakdownpotential of the gas of said lamp.

9. A lamp comprising an envelope, an anode within said envelope, acathode within said envelope but spaced from said anode, an ionizablegas within the envelope, a restricted passage between said anode andcathode, releasable means for holdingsaid lamp in operative positionwith reference to an electric circuit whereby a diiference of potentialis applied between the anode and cathode, and additional separable meansincluding a conductor adapted to contact the exterior surface of theenvelope between the anode and cathode and effective only when said lampis in said operative position for modifying the breakdown potential ofthe gas of said lamp.

ARNO ZILLGER.

